The present disclosure relates to a fuel supply device for supplying fuel from a fuel tank on a vehicle to an internal combustion engine such as a vehicle engine.
Conventional fuel supply devices have been disclosed in, for example, Japanese Laid-Open Patent Publication No. 2012-184760. The fuel supply device includes a cover-side unit, a pump-side unit, and a coupling mechanism. The cover-side unit is configured to close an opening that is formed on an upper wall of a fuel tank of a vehicle or the like. The pump-side unit includes a fuel pump which may be disposed within the fuel tank. The coupling mechanism is configured to couple the pump-side unit to the cover-side unit in a slidable manner in the vertical direction.
As shown in FIG. 9, the coupling mechanism 200 includes a fixed-side rail member 204 provided as part of the cover-side unit 202 and a movable-side rail member 208 provided as part of the pump-side unit 206. The fixed-side rail member 204 includes a rail portion 205 linearly extending in the vertical direction (going into and out of the page of FIG. 9). The movable-side rail member 208 has a rail groove 210 that assumes the shape of a channel groove so as to slidably engage with the rail portion 205 of the fixed-side rail member 204. The rail groove 210 is formed with an inner end face 211 and a pair of groove lateral faces 212. Round chamfered portions 213 are formed at the intersection of both corners defined by the ends of inner end face 211 and both groove lateral faces 212.
Although, as shown in FIG. 9, both corners of the rail groove 210 of the movable-side rail 208 are formed with the chamfered portions 213, the curvature radius of each chamfered portion 213 is small. Therefore, if the vehicle is involved in a collision, the stress concentrations due to such a collision may disproportionately arise at the corners (chamfered portions 213) of the rail groove 210 of the movable-side rail member 208. As a result, damage such as a crack may form at the corners. In order to relieve the stress due to the collision, the curvature radius of the chamfered portions 213 may be increased. However, if the curvature radii of the chamfered portions 213 are increased, the chamfered portions 213 may interfere with the leading end (right end in FIG. 9) of the rail portion 205 of the fixed-side rail member 204. Therefore, it is difficult to increase the curvature radii of the chamfered portions 213. Accordingly, there is a need for a fuel supply device that reduces stress concentrations at the corners of a rail groove of a movable-side rail member while simultaneously avoiding interference with a rail portion of a fixed-side rail member.